What is understood by a two-side working machine is a machine which has an upper and a lower working disc between which flat workpieces are machined which are to be provided with parallel-plane surfaces. Machines of this type serve for polishing, lapping or even grinding.
A two-side grinding machine has become known from DE 102 29 941 A1, the entire contents of which are incorporated herein by reference, for example. Two-side grinding machines have also been known from DE 199 37 748 A1, the entire contents of which is incorporated herein by reference, or DE 690 24 681 T2, the entire contents of which is incorporated herein by reference.
From US 2006/0040589 A1, the entire contents of which is incorporated herein by reference, it has become known to measure the gap distance in at least two radially spaced points by means of a suitable distance measuring device, and to regulate the supply of the coolant to the working discs in dependence on the values measured.
Since the workpieces are moved within the gap between the upper and lower working discs their geometry is significantly determined by the geometry of the working discs. Stability of temperature during the working process is an important criterion for manufacturing high-quality workpieces. This is why the temperature needed in working is set inside a labyrinth which is arranged between the carrier disc and working disc and in which a coolant is circulated. Normally, temperature-controlled water is pumped through the channel system which is installed.
The common construction of such working machines provides that the working disc proper bears on a carrier disc which, in turn, is coupled to a shaft which is set into rotation by an appropriate driving motor. Since temperature conditions vary on the working disc the disc will get deformed and causes an irregular working gap. Although the distance measurement mentioned allows to ascertain the occurrence of such a deformation it is not always possible to compensate such deformations by adequately influencing the temperature or purposefully cooling the disc.
Therefore, it is the object of the invention to provide a two-side working machine which helps achieve an intentional deformation of the upper working disc, particularly for leveling out undesirable variations of the working gap as a result of a deformation of the working disc.